<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html ng-app="app">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script type="text/javascript" src="js/angular.min.js"></script>
<style>
<!--
*{padding:0; margin:0}
body{font-size:12px}
select{height:22px; line-height:18px; padding:2px 0}
-->
</style>
</head>
<body >
	<input id="aa">
<div style="margin-top:20px; margin-left:20px; background:#000"  ng-controller="searchdata" >

‍‍<select id="pid" ng-change="change(x)" ng-model="x">
    <option grade="1" value="a">选项一</a>
    <option grade="2" value="b">选项二</a>

</select>
</div>
<script>
var app=angular.module("app",[]);
			app.controller('searchdata',function($scope){
				$scope.x=document.getElementById('pid').value;
				document.getElementById('aa').placeholder='选择一';
				$scope.change=function(x){
					console.log(x);
       // var objS = document.getElementById("pid");
        //var grade = objS.options[objS.selectedIndex].value;
       // console.log(grade);
        //var sel =document.getElementById('pid').value;
        //console.log(sel);
       /* var h=document.getElementById('pid').value;*/
			
           switch(x){
           	case 'a':
       		document.getElementById('aa').placeholder='选择一';
            break;
            case 'b':
            document.getElementById('aa').placeholder='选择2';
            break;
				};
				
				
			}
			});
	
       
</script>
</script>
</body>
</html>